System, method and devices for enabling efficient hybrid route optimization between two mobile endpoints

ABSTRACT

A network, a method and devices (i.e., mobile node, access router, home agent, destination home agent) are described herein for enabling an efficient hybrid route optimization between two mobile endpoints so they can re-direct their data traffic to an optimal path without exchanging any mobility signaling messages.

CLAIMING BENEFIT OF PRIOR FILED U.S. APPLICATIONS

This patent application is a continuation application of U.S. patentapplication Ser. No. 12/828,811, filed Jul. 1, 2010, now U.S. Pat. No.8,385,285, which claims the benefit of U S. Provisional Application Ser.No. 61/263,333 filed on Nov. 20, 2009. The contents of these documentsare hereby incorporated by reference herein.

TECHNICAL FIELD

The present invention relates in general to the wirelesstelecommunications field and, in particular, to a network, a method anddevices (i.e., mobile node, access router, home agent, destination homeagent) for enabling an efficient hybrid route optimization between twomobile endpoints so they can re-direct their data traffic to an optimalpath without exchanging any mobility signaling messages,

BACKGROUND

The following abbreviations are herewith defined, at least some of whichare referred to within the following description of the prior art andthe present invention.

-   AR Access Router-   BA Binding Acknowledgement-   BCE Binding Cache Entry-   BU Binding Update-   CoA Care-of Address-   CN Correspondent Node-   D-HA Destination Home Agent-   HA Home Agent-   HD High Definition-   HoA Home Address-   IETF Internet Engineering Task Force-   IP Internet Protocol-   LTE Long Term Evolution-   MAG Mobility Access Gateway-   MN Mobile Node-   NoA Notification Acknowledgment-   NoU Notification Update-   PBU Proxy Binding Update-   PNA Presence Notification Acknowledgment-   PNU Presence Notification Update-   RNA Register Notification Acknowledgment-   RNR Register Notification Request-   RO Route Optimization-   SQN Sequence Number

The Internet Engineering Task Force (IETF) has recently been focused onwhat is known in the wireless communications field as the hybrid routeoptimization (RO) mode which allows both a mobile node and the networkinfrastructure to take different responsibilities to provide an optimalIP handoff. The hybrid RO mode is a mixture of host-based mobility andnetwork-based mobility which is desired and perhaps required to enableoperators to closely assist the mobile node in selecting the right pathfor exchanging data packets with a correspondent node (i.e. a peer forthe mobile node). The mixture of host-based mobility and network-basedmobility is also desired to enable operators to control and optimizetheir available bandwidth, optimize the mobile device's powerconsumption while providing a high quality of service. However, there isno existing solution associated with hybrid RO mode that takes intoconsideration the scenario of two mobile nodes talking to each other.This “dual mobility endpoints” scenario in which two mobile nodes talkto each other is going to have tremendous and continuous growth due tothe popularity of smart phones (e.g., IPhones) which can be coupledtogether with high speed wireless channels that are expected to beprovided by LTE. Consequently, the likelihood of establishing HDmultimedia sessions between two mobile nodes will only increase in thefuture. Accordingly, there is a need to improve the hybrid RO mode toaddress the dual mobility endpoint scenario. This need and other needshave been addressed by the present invention.

SUMMARY

A method, a network, an access router, a home agent, and a destinationhome agent are described in the independent claims of the presentapplication. Advantageous embodiments of the method, the network, theaccess router, the home agent, and the destination home agent aredescribed in the dependent claims.

In one aspect, the present invention provides a method for enabling ahybrid route optimization in a network between two mobile endpointsincluding a MN and a CN, wherein the MN is associated with a HA and theCN is associated with a D-HA, and wherein the MN is able to move aroundand attach to anyone of a plurality of ARs. The method includes at leastlive steps where the first step includes sending a first message fromthe MN to the HA, wherein the first message includes an InternetProtocol address of the CN, and wherein the HA uses the InternetProtocol address to identify the D-HA. The second step includes sendinga second message from the HA to at least one of the ARs, wherein thesecond message includes information about the MN, the CN, and the D-HA.The third step includes sending a third message from the at least one ofthe ARs to the D-HA, wherein the third message subscribes the at leastone of the ARs at the D-HA for a

presence notification service in which the D-HA is to update the atleast one of the ARs about a care-of address of the CN whenever the CNsends the care-of address to the D-HA. The fourth step includes sendinga. fourth message from the D-HA to the at least one of the ARs, whereinthe fourth message identifies the care-of address of the CN. The fifthstep includes one of the at least one of the ARs that is attached to theMN upon receiving the fourth message sending a fifth message to the MN,wherein the fifth message includes the care-of address of the CN whichenables a re-direction of data traffic between the MN and the CN. Themethod has an advantage in that it enables an efficient hybrid routeoptimization between two mobile endpoints namely the MN and CN so theycan re-direct their data traffic to an optimal path without exchangingany mobility signaling messages.

In yet another aspect, the present invention provides a network forenabling a hybrid route optimization between two mobile endpointsincluding a MN and a CN, wherein the MN is associated with a HA and theCN is associated with a D-HA, and wherein the MN is able to move aroundand attach to anyone of a plurality of ARs. The MN sends a first messageto the HA, wherein the first message includes an Internet Protocoladdress of the CN, and wherein the HA uses the Internet Protocol addressto identify the D-HA. The HA sends a second message to at least one ofthe ARs. wherein the second message includes information about the MN,the CN, and the D-HA. The at least one of the ARs sends a third messageto the D-HA, wherein the third message subscribes the at least one ofthe ARs at the D-HA for a presence notification service in which theD-HA is to update the at least one of the ARs about a care-of address ofthe CN whenever the. CN sends the care-of address to the D-HA, The D-HAsends a fourth message to the at least one of the ARs, wherein thefourth message identifies the care-of address of the CN. The AR thatreceives the fourth message and is attached to the MN sends a fifthmessage to the MN, wherein the fifth message includes the care-ofaddress of the CN which enables a re-direction of data traffic betweenthe MN and the CN. The network has an advantage in that it enables anefficient hybrid route optimization between two mobile endpoints namelythe MN and CN so they can re-direct their data traffic to an optimalpath without exchanging any mobility signaling messages.

In still yet another aspect, the present invention provides an AR forenabling a hybrid route optimization between two mobile endpointsincluding a MN and a CN, wherein the MN is attached to the AR andassociated with a HA, wherein the CN is associated with a D-HA, whereinthe MN sends a first message to the HA, wherein the first messageincludes an IPv6 address of the CN, and wherein the HA uses the IPv6address to identify the D-HA. The AR comprises a processor and a memorythat stores processor-executable instructions wherein the processorinterfaces with the memory and executes the processor-executableinstructions to perform at least. four steps. The first step is toreceive a second message from the HA, wherein the second messageincludes information about the MN, the CN, and the D-HA. The second stepis to send a third message to the D-HA, wherein the third messagesubscribes the AR at the D-HA for a presence notification service inwhich the D-HA is to update the AR about a care-of address of the CNwhenever the CN sends the care-of address to the D-HA. The third step isto receive a fourth message from the D-HA, wherein the fourth messageidentifies the care-of address of the CN. The fourth step is to send afifth message to the MN, wherein the fifth message includes the care-ofaddress of the CN which enables a re-direction of data traffic betweenthe MN and the CN. The AR has an advantage in that it enables anefficient hybrid route optimization between two mobile endpoints namelythe MN and CN so they can re-direct their data traffic to an optimalpath without having to exchange any mobility signaling messages.

In still yet another aspect, the present invention provides a HA forenabling a hybrid route optimization between two mobile endpointsincluding a MN and a CN, wherein the MN is associated with the HA,wherein the CN is associated with a D-HA, wherein the MN is able to movearound and attach to anyone of a plurality of ARs, The HA includes aprocessor and a memory that stores processor-executable instructionswherein the processor interfaces with the memory and executes theprocessor-executable instructions to perform at least three steps. Thefirst step is to receive a first message from the MN, wherein the firstmessage includes an IP address of the CN. The second step is to use theIP address to identify the D-HA. The third step is to send a secondmessage to at least one of the ARs, wherein the second message includesinformation about the MN, the CN, and the D-HA, wherein the at least oneof the ARs sends a third message to the D-HA, wherein the third messagesubscribes the at least one of the ARs at the D-HA for a presencenotification service in which the D-HA is to update the at least one ofthe ARs about a care-of address of the CN whenever the CN sends thecare-of address to the D-HA. wherein the D-HA sends a fourth message tothe at least one of the ARs, wherein the fourth message identifies thecare-of address of the CN, and wherein the one AR that receives thefourth message and is attached to the MN sends a fifth message to theMN, wherein the fifth message includes the care-of address of the CNwhich enables a re-direction of data traffic between the MN and the CN.The HA has an advantage in that it enables an efficient hybrid routeoptimization between two mobile endpoints namely the MN and CN so theycan re-direct their data traffic to an optimal path without having, toexchange any mobility signaling, messages.

In yet another aspect, the present invention provides a D-HA forenabling a hybrid route optimization between two mobile endpointsincluding a MN and a CN. The MN is associated with a HA and the CN isassociated with the D-HA. The MN is able to move around and attach toanyone of a plurality of ARs. The MN sends a first message to the HA.wherein the first message includes an IP address of the CN. The HA usesthe IP address to identify the D-HA. The HA sends a second message to atleast one of the ARs, wherein the second message includes informationabout the MN, the CN, and the D-HA. The D-HA includes a processor and amemory, that stores processor-executable instructions wherein theprocessor interfaces with the memory and executes theprocessor-executable instructions to perform at least two steps. Thefirst step is to receive a third message from the at least one of theARs, wherein the third message subscribes the at least one of the ARs atthe D-HA for a presence notification service in which the D-HA is toupdate the at least one of the ARs about a care-of address of the CNwhenever the CN sends the care-of address to the D-HA. The second stepis to send a fourth message to the at least one of the ARs, wherein thefourth message identifies the care-of address of the CN, wherein the ARthat receives the fourth message and is attached to the MN sends a fifthmessage to the MN, and wherein the fifth message includes the care-ofaddress of the UN which enables a re-direction of data traffic betweenthe MN and the CN. The D-HA has an advantage in that it enables anefficient hybrid route optimization between two mobile endpoints namelythe MN and UN so they can re-direct their data traffic to an optimalpath without having to exchange any mobility signaling messages.

The present invention also provides a HA for enabling a hybrid routeoptimization between two mobile endpoints including a MN and a CN,wherein the MN is associated with the HA and the UN is associated with aD-HA, and wherein the MN is able to move around and attach to anyone ofa plurality of ARs, The HA includes: (a) a processor; and (b) a memorythat stores processor-executable instructions wherein the processorinterfaces with the memory and executes the processor-executableinstructions to: (i) receive a first message from the MN, wherein thefirst message includes an Internet Protocol address of the CN; (ii) usethe Internet Protocol address to identify the D-HA; (iii) send a secondmessage to the D-HA, wherein the second message subscribes the HA at thefor a presence notification service in which the D-HA is to update theHA about a care-of address of the CN whenever the CN sends the care-ofaddress to the D-HA; (iv) receive a third message from the D-HA, whereinthe third message identifies the care-of address of the CN; and (v) senda fourth message to the MN, wherein the fourth message includes thecare-of address of the UN which enables a re-direction of data trafficbetween the MN and the CN. The HA has an advantage in that it enables anefficient hybrid route optimization between two mobile endpoints namelythe MN and CN so they can re-direct their data traffic to an optimalpath without having to exchange any mobility signaling messages.

Additional aspects of the invention will be set forth, in part, in thedetailed description, figures and any claims which follow, and in partwill be derived from the detailed description, or can be learned bypractice of the invention. It is to be understood that both theforegoing general description and the following detailed description areexemplary and explanatory only and are not restrictive of the inventionas disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be obtainedby reference to the following detailed description when taken inconjunction with the accompanying drawings:

FIG. 1 is a block diagram of an exemplary network configured to enablean efficient hybrid RO mode between two mobile endpoints namely a MN andCN in accordance with an embodiment of the present invention;

FIG. 2 is a flowchart illustrating the steps of an exemplary method forenabling an efficient hybrid route optimization between two mobileendpoints namely the MN and the CN in accordance with an embodiment ofthe present invention:

FIG. 3 is a block diagram of the exemplary network which is used to helpexplain in greater detail step 202 of the method 200 shown in FIG. 2 inaccordance with an embodiment of the present invention;

FIG. 4 is a block diagram of the exemplary network which is used to helpexplain in greater detail steps 204 and 206 of the method 200 shown inFIG. 2 in accordance with an embodiment of the present invention;

FIG. 5 is a block diagram of the exemplary network which is used to helpexplain in greater detail step 208 of the method 200 shown in FIG. 2 inaccordance with an embodiment of the present invention; and

FIG. 6 is a block diagram of the exemplary network which is used to helpexplain in greater detail steps 210 and 212 of the method 200 shown inFIG. 2 in accordance with an embodiment of the present invention,

DETAILED DESCRIPTION

Referring to FIG. 1, there is a block diagram of an exemplary network100 configured to enable an efficient hybrid RO mode between two mobileendpoints in accordance with an embodiment of the present invention. Theexemplary network 100 includes an interconnecting network 101 whichcouples a MN 102, a CN 104 (i.e. a peer for the MN 102), a HA 106(associated with the MN 102), a D-HA 108 (associated with the UN 104), afirst AR 110 (e.g., first MAG 110), a second AR 112 (e.g., second MAG112), a third AR 114 (e.g., third MAG 114), and a fourth AR 116 (e.g.,fourth MAG 116), The HA 106 can identify the D-HA 108 and communicatesecurely with the D-HA 108 and the ARs 110, 112, 114 which could bevisited by the MN 102, The ARs 110, 112, 114, 116 can communicate withboth the HA 106 and the D-HA 108. in this example, the MN102 is shown asbeing currently attached to the second AR 112 but the MN 102 is mobileand can potentially move to and attach to either the first AR 110 or thethird AR 114. The CN 104 is shown as being currently attached to theD-HA 108 but the CN 104 is mobile and can potentially move to and attachto the fourth AR 116. Alternatively, the UN 104 may move around the sameset of ARs 110, 112, and 114 associated with the MN 102 or withinanother set of ARs 116 which do not intersect with the ARs 110, 112, and114.

The exemplary network 100 includes many other components that are wellknown in the art but for clarity are not described herein while thecomponents 102, 104, 106, 108, 110, 112, 114, 116 which are relevant tothe present invention are described in detail herein. In particular, adetailed description about the functionality of the components 102, 104,106, 108, 110, 112, 114 and 116 is provided next to explain how toenable the hybrid HO mode for the two mobile endpoints including the MN102 and the CN 104 so they can re-direct their data traffic to theoptimal path without exchanging any mobility signaling messages.

Referring to FIG. 2, there is a flowchart illustrating the steps of anexemplary method 200 for enabling an efficient hybrid route optimizationbetween two mobile endpoints namely the MN 102 and the CN 104 inaccordance with an embodiment of the present invention. The method 200includes the following general steps which are described in greaterdetail below:

1. MN 102 sends a message (i.e., BU message) to the HA 106 whichnotifies the HA 106 about the IPv6 address of the CN 104 (see step 202and FIG. 3).

2. HA 106 identifies and possibly subscribes for a “presence” servicewith the D-HA 108 (see step 204 and FIG. 4).

3. HA 106 updates one or more of the potential ARs 110. 112, and 114 bysending them a message (i.e., NoU message) which includes informationabout the MN 102, the CN 104, and the D-HA 108 (see step 206 and FIG.4).

4. Each potential AR 110, 112 and 114 sends a message i.e., RNR message)to the D-HA 108 to subscribe for a presence service to receive updatesabout CN 104 (see step 208 and FIG. 5). In a simpler deployment, onlythe AR 112 which is currently attached to the MN 102 sends the messageto the D-HA 108. In one application, the HA is 106 could explicitlyrequest that the ARs 110, 112 and 114 send the RNR message to the D-HA108.

5. When the CN 104 updates the D-HA 108 with a new CoA, then the D-HA108 sends a message (i.e., PNU message) to immediately update each AR110, 112 and 114 and possibly the HA 106 which have previouslysubscribed for a presence service related to the CN 104 (see step 210and FIG. 6).

6. The AR 110, 112 or 114 that is attached to and hosting, the MN 102immediately sends a message (i.e., early update message) to the MN 102to update the MN 102 about the current location (CoA) of the CN 104 sothat the hybrid RO mode can always be used (see step 212 and FIG. 6).

The exemplary method 200 ensures that the hybrid. RO mode can he usedbetween two mobile endpoints namely the MN102 and CN 104 whileminimizing/removing the exchange of signalling messages on the MN 102side which enables a significantly faster IP handoff, The exemplarymethod 200 which is described in greater detail below is based on thefollowing assumptions:

-   -   The MN 102 has at least one HA 106 and the later is able to        identify and communicate with other HAs located in other        operators networks such as the D-HA 108. To avoid potential        confusion between the different HAs 106 and 108, the MN's home        agent is referred to herein as HA 106 and to the CN's home agent        is referred to herein as D-HA 108.    -   The communication is secured between the HA 106 and the D-HA        108.    -   The HA 106 can securely communicate with any AR 110, 112, and        114 which is capable to securely exchange a Proxy Binding Update        (PBL) and a Proxy Binding Acknowledgment (PBA) with the HA 106        in a Proxy MIPv6 context.    -   The ARs 110, 112 and 114 which can communicate securely with the        HA 106 can also establish a secure communication with the D-HA        108.    -   The MN 102 can authenticate any of the ARs 110, 112 and 114 upon        attachment to the associated link.

Referring to FIG. 3, there is a block diagram of the exemplary network100 shown to help explain in greater detail step 202 of the method 200in accordance with an embodiment of the present invention. The firststep 202 starts when the MN 102 notifies the HA about the CN's IPv6address and its destination. Such notification occurs when the MN 102switches to another network in order to allow the HA 106 to takeactions. The decision to notify (or not) the HA 106 about the CN's IPv6address can be based on the type of applications used by the MN 102,i.e., policy-dependent. In this discussion, assume that the MN 102notifies its HA 106. For instance, the notification itself can be abinding update (BU) message 302 sent by the MN 102 to the HA 106. Inthis scenario, the BU message would carry the CN's IPv6 address andpossibly other parameters, e.g., flow(s) identifier(s), geographicdestination. Upon receiving a valid BU message 302, the HA 106 takesimmediate actions (detailed below) and replies to the MN 102 by sendinga binding acknowledgment (BA) message 304.

Referring to FIG. 4, there is a block diagram of the exemplary network100 shown to help explain in greater detail steps 204 and 206 of themethod 200 in accordance with an embodiment of the present invention.After creating a binding cache entry for the MN 102, and in parallelwith sending the BA message 304 to the MN 102, the HA 106 can performstep 204 and subscribe for a presence service to monitor the CN 104 withthe D-HA 108. This is done by the HA 106 sending a message calledRegister Notification Request (RNR) message 402 to the D-HA 108. The RNRmessage 402 includes the CN's IP address, the HA's “Proof-of-Interest”,e.g., its certificate, the MN's HoA and a lifetime. The D-HA 108 repliesby sending a message called Register Notification Acknowledgment (RNA)message 404 back to the HA 106. In this scenario, assume the HA 106subscribes for a presence service with the D-HA 108 to monitor the CN104.

Thereafter, the HA 106 performs step 206 and contacts potential ARs 110,112 and 114 which may receive the MN 102 on their associated link (i.e.,including, the current one). As shown, the HA 106 does this by sending amessage called Notification Update (NoU) message 406 to each of the ARs110, 112 and 114 (unicast mode). Alternatively, the HA 106 can send oneNoU message 406 to all of the ARs 110, 112 and 114 (multicast mode). Ina simpler deployment, the HA 106 can send the NoU message 406 to onlythe AR 112 that is currently attached to the MN 102. In this scenario,assume the HA 106 sends the NoU message 406 to ARs 110, 112 and 114. TheNoU message 406 carries the MN's home address (HoA), the MN's care-ofaddress (CoA), the targeted CN's IP address, the D-HA's IP address, alifetime, and a sequence number (i.e., a set of six parameters {HoA,CoA, CN, DHA, lifetime, SQN}). Each AR 110, 112 and 114 that receivesthe NoU message 406 creates an entry in cache memory which stores theMN's six associated parameters with the MN's HA IP address. The new RNR,RNA, NoU messages 402, 404 and 406 should he protected. If the AR 110,112 or 114 is a MAG then the NoU message 406 may be piggybacked in aProxy BA (PBA) message sent by the HA 10 to the MAG, i.e., uponreceiving a PBU message related to the MN 102.

Referring to FIG. 5, there is a block diagram of the exemplary network100 shown to help explain in greater detail step 208 of the method 200in accordance with an embodiment of the present invention. Uponreceiving the valid NoU message 406, each AR 110, 112 and 114 performsstep 208 by sending a message called Register Notification Request (RNR)message 502 to the D-HA 108. The RNR messages 502 allow the ARs 110,112, and 114 to subscribe at the D-HA 108 for a particular service(i.e., Presence Notification). In return, the D-HA 108 constantlyupdates each subscribed AR 110, 112 and 114 about the whereabouts of theCN 104 for the associated lifetime sent in the message 502. Each RNRmessage 502 carries the CN's IP address, AR certificate (optional), theMN's HoA (optional), the lifetime sent by the HA 106 in the NoU message406 and a sequence number. Each RNR message 502 should be encrypted andintegrity protected. In addition to sending the RNR messages 502, eachAR 110, 112 and 114 replies to the HA 106 by sending, a message calledNotification Acknowledgment (NoA) message 504 in response to receivingthe NoU message 406. The NoA messages 504 carry the D-HA's IP address,the lifetime, the CN's CoA, and the SQN, The NoA messages 504 shouldalso be encrypted and integrity protected.

Upon receiving the RNR messages 502, the D-HA 108 processes the RNRmessages 502 and stores the IP addresses of the ARs 110, 112 and 114together with the requested CN's IP address, and the same lifetime andpossibly the SQN sent in the NoU message 406 (i.e., and copied in theRNR messages 502). The D-HA 108 then replies to each AR 130, 112 and 114with a new message called Registration for Notification Acknowledgment(RNA) message 506 which carries the CN's IP address and the lifetime.Starting from this moment, each time the CN 104 updates the ID-HA 108with a new CoA, the D-HA 108 will immediately notify all the ARs 110,112 and 114 which have subscribed to a presence service associated withthe CN 104. In addition the D-HA 108 would notify the MN's HA 106 whichin this scenario has also subscribed to a presence service associatedwith the CN 104.

Referring to FIG. 6, there is a block diagram of the exemplary network100 shown to help explain in greater detail steps 210 and 212 of themethod 200 in accordance with an embodiment of the present invention. Asmentioned earlier, the HA 106 and ARs 110, 112 and 114 by registeringfor a presence service means that the HA 106 and each AR 110, 112 and114 is entitled to receive an immediate and secure update from the D-HA10$ regarding the whereabouts (i.e., CoA) of the CN 104. The presenceservice should last until the expiration of the lifetime sent in the RNRand RNA messages 402, 404, 502 and 506 exchanged between the D-HA 108and both the HA 106 and the ARs 110, 112 and 114. Plus, each time the CN104 refreshes its BU lifetime stored in the D-HA 108, the D-HA 108should update the registered HA 106 and ARs 110, 112 and 114 with thenew lifetime.

In this regard, upon receiving a BU message 602 from the CN 104(recently moved to AR 116) carrying a new CoA, the D-HA 108 sends instep 210 a new message called Presence Notification Update (PNU) message604 to the HA 106 and each AR 110, 112 and 114. The PNU message 604carries the CN's new CoA, the same lifetime and a SQN used in the RUmessage 602 exchanged between the CN 104 and the D-HA 108, The PNUmessage 604 should be encrypted and integrity protected. The HA 106 andARs 110, 112 and 114 should acknowledge receipt of a valid PNU message604 by sending a message called Presence Notification Acknowledge (PNA)message 606 to the D-HA 108, which carries the CN's new CoA and the SQNsent in the PNU message 604. The PNA message 606 should be encrypted andintegrity protected.

The receipt of a valid PNU message 604 is immediately followed by thesending of an early update message 608 (containing the CN's CoA) perstep 212 from the AR 112 (for example) which is hosting the MN 102. TheMN 102 upon receiving the early update message 608 can quickly re-directdata traffic to the new direct path to the CN 104. In this way, there-direction of the data traffic does not require any mobility signalingmessages exchange between the two endpoints namely the MN 102 and CN104. Upon the MN 102 returning to its home, the HA 106 shouldde-register all Alts 110. 112 and 114 which have subscribed earlier tothe D-HA 108. For instance, the HA 106 can do this by requesting theD-HA 108 to stop refreshing the lifetime sent to each AR 110, 112 and114 that has registered for the presence service for the particular MN102, Consequently, Whenever the lifetime associated with a presenceservice expires the AR 110, 112 and 114 flushes the corresponding datastored within its cache.

In an alternative embodiment, the MN's HA 106 can be the first (andonly) entity which subscribes to a presence service for any mobile CN104 which is exchanging data packets with the MN 102. In this case, theMN's HA 106 will be responsible for updating the MN 102 with the new CoAof the CN 104 by sending the MN 102 a direct message which enables thetwo endpoints to keep using the RO mode (or to fallback to the BT modeif needed). However, such an exchange may increase the overall latencyand would not be as efficient as the hosting AR 112 sending the earlyupdate message 608 to the MN 102. On the other hand, if the HA 106 doessend the direct message to the MN 102 then the ARs 110, 1.12 and 114would not have to register for the presence notification service withthe D-HA 108.

From the foregoing, one skilled in the art will appreciate that thepresent invention is aimed, at least, to provide a ‘Hybrid’ RouteOptimization mode, which enables two mobile endpoints (i.e., MN 102 andCN 104) to re-direct their data traffic to the optimal. path withoutexchanging an mobility signaling messages. To accomplish this, thepresent invention introduces a new service between the HA 106, D-HA 108and the ARs 110, 112 and 114 called “presence” service. The “presence”service is an explicit request/reply exchange between the D-HA 108 andthe HA 106 and/or ARs 110, 112 and/or 114 which are interested intracking the movement of a specific target (i.e., CN 104). Such requestscarry a “Proof-of-Interest (PoI)” and should be protected. In itssimplest form, a “Proof-of-Interest” can be the sender's certificate,which mentions its role as for instance a HA 106 for a specific MN 102(e.g., advertise the same prefix used by the MN 102). When accepting arequest for subscription to a “presence” service, the receiving D-HA 108replies to the sender (e.g.. HA 106, ARs 110, 112 and/or 114) by sendingthem an ACK message. The sender's IP address is then stored in the cachememory of the receiving D-HA 108 together with the requested target's IPaddress and a lifetime (other parameters can also be stored). As can beseen, multiple entities HA 106 and/or ARs 110, 112 and/or 114 maysubscribe for a presence service that is related to the same target CN104, Until the lifetime expiration, each time the specified target CN104 updates its own D-HA 108 with a new CoA, the target's D-HA 108 inturn immediately update all of the entities (i.e., HA 106 and/or ARs110, 112 and/or 114) which are subscribed to a “presence” serviceinvolving the specific target CN 104. When a presence service lifetimeexpires, the target's D-HA 108 removes the associated entry from itscache memory unless a renewal message is received.

The present invention also provides a MN 102 for enabling a hybrid routeoptimization with another mobile CN 104, wherein the MN 102 isassociated with a HA. 102 and the CN 104 is associated with a D-HA 108,and wherein the MN 102 is able to move around and attach to anyone of aplurality of ARs 110, 112 and 114. The MN 102 includes: (a) a processor130; and (b) a memory 132 that stores processor-executable instructionswhere the processor 130 interfaces with the memory 132 and executes theprocessor-executable instructions to: (i) send as first message 302 tothe HA 106, wherein the first message 302 includes an IP address of theCN 104. wherein the HA 106 uses the IP address to identify the D-HA 108,wherein the HA 106 sends a second message 406 to at least one of the ARs110, 112 and 114, wherein the second message 406 includes informationabout the MN 102, the CN 104, and the D-HA 108, wherein the at least oneof the ARs 110, 112 and 114 sends a third message 502 to the D-HA 108,wherein the third message 502 subscribes the at least one of the ARs110, 112 and 114 at the D-HA 108 for a presence notification service inwhich the D-HA 108 is to update the at least one of the ARs 110, 112 and114 about a care-of address of the CN 104 whenever the CN 104 sends thecare-of address to the D-HA 108, wherein the D-HA 108 sends a fourthmessage 606 to the at least one of the ARs 110, 112 and 114, wherein thefourth message 606 identifies the care-of address of the CN 104, and(ii) receive a fifth message 608 from one of the at least one ARs 110,112 and 114 that is attached to the MN 102, wherein the fifth message608 includes the care-of address of the CN which enables as re-directionof data traffic between the MN 102 and the CN 104. The MN 102 can alsoimplement a method which includes the two aforementioned steps (i) and(ii).

The present invention also provides an AR 112 (for example) for enablinga hybrid route optimization between two mobile endpoints including a MN102 and a CN 104, wherein the MN 102 is attached to the AR 112 andassociated with a HA 106 and the CN 106 is associated with a D-HA 108,wherein the MN 102 sends a first message 302 to the HA 106, wherein thefirst message 302 includes an IP address of the CN 104, and wherein theHA 106 uses the IP address to identify the D-HA 108 The AR 112comprises: (a) a processor 134; and (b) a memory 136 that storesprocessor-executable instructions wherein the processor 134 interfaceswith the memory 136 and executes the processor-executable instructionsto: (i) receive a second message 406 from the HA 106, wherein the secondmessage 406 includes information about the MN 102, the CN 104, and theD-HA 108; (ii) send a third message 502 to the D-HA 108, wherein thethird message 502 subscribes the AR 112 at the D-HA 108 for a presencenotification service in which the D-HA 108 is to update the AR 112 abouta care-of address of the CN 104 whenever the CN 104 sends the care-ofaddress to the D-HA 108; (iii) receive a fourth message 606 from theD-HA 108, wherein the fourth message 606 identifies the care-of addressof the CN 104; and (iv) send a fifth message 608 to the MN 102, whereinthe fifth message 608 includes the care-of address of the CN 104 whichenables a re-direction of data traffic between the MN 102 and the CN104. The AR 112 can also implement a method which includes the fouraforementioned steps (i), (ii), (iii) and (iv).

The present invention also provides an HA 106 for enabling a hybridroute optimization between two mobile endpoints including a MN 102 and aCN 104, wherein the MN 102 is associated with the HA 106 and the CN 104is associated with a D-HA 108, wherein the MN 102 is able to move aroundand attach to anyone of a plurality of ARs 110, 112 and 114. The HA 106includes: (a) a processor 138; and (b) a memory 140 that storesprocessor-executable instructions wherein the processor 138 interfaceswith the memory 140 and executes the processor-executable instructionsto: (i) receive a first message 302 from the MN 102, wherein the firstmessage 302 includes an IP address of the CN 104; (ii) use the IPaddress to identify the D-HA 108; (iii) send a second message 406 to atleast one of the ARs 110, 112 and 114, wherein the second message 406includes information about the MN 102, the CN 104, and the D-HA 108,wherein the at least one of the ARs 110, 112 and 114 sends a thirdmessage 502 to the D-HA 108, wherein the third message 502 subscribesthe at least one of the ARs 110, 112 and 114 at the D-HA 108 for apresence notification service in which the D-HA 108 is to update the atleast one of the ARs 110, 112 and 114 about a care-of address of the CN104 whenever the CN 104 sends the care-of address to the D-HA 108,wherein the D-HA 108 sends a fourth message 606 to the at least one ofthe ARs 110, 112 and 114, wherein the fourth message 606 identifies thecare-of address of the CN 104, and wherein one of the at least one ofthe ARs 110, 112 and 114 that receives the fourth message 606 and isattached to the MN 102 sends a fifth message 608 to the MN 102, andwherein the fifth message 608 includes the care-of address of the CN 104which enables a re-direction of data traffic between the MN 102 and theCN 104. The HA 106 can also implement a method which includes the threeaforementioned steps (i), (ii) and (iii).

The present invention also provides a D-HA 108 for enabling a hybridroute optimization between two mobile endpoints including a MN 102 and aCN 104, wherein the MN 102 is associated with a HA 106 and the CN 104 isassociated with the D-HA 108, wherein the MN 102 is able to move aroundand attach to anyone of a plurality of ARs 110, 112 and 114, wherein theMN 102 sends a first message 302 to the HA 106, wherein the firstmessage 302 includes an IP address of the CN 104. wherein the HA 106uses the IP address to identify the D-HA 108, wherein the HA 106 sends asecond message 406 to at least one of the ARs 110, 112 and 114, whereinthe second message 406 includes information about the MN 102, the CN104, and the D-HA 108. The D-HA 108 includes: (a) a processor 142; and(h) a memory 144 that stores processor-executable instructions whereinthe processor 142 interfaces with the memory 144 and executes theprocessor-executable instructions to: (i) receive a third message 502from the at least one of the ARs 110, 112 and 114, wherein the thirdmessage 502 subscribes the at least one of the ARs 110, 112 and 114 atthe D-HA 108 for a presence notification service in which the D-HA 108is to update the at least one of the ARs 110, 112 and 114 about acare-of address of the CN 104 whenever the CN 104 sends the care-ofaddress to the D-HA 108; (ii) send a fourth message 606 to the at leastone of the ARs 110, 112 and 114 wherein the fourth message 606identifies the care-of address of the CN 104, wherein one of the atleast one of the ARs 110, 112 and 114 that receives the fourth message606 and is attached to the MN 102 sends a fifth message 608 to the MN102, and wherein the fifth message 508 includes the care-of address ofthe CN 104 which enables a re-direction of data traffic between the MN102 and the CN 104. The D-HA 108 can also implement a method whichincludes the two aforementioned steps (i) and (ii).

The present invention also provides as HA 106 for enabling, a hybridroute optimization between two mobile endpoints including a MN 102 and aCN 104, wherein the MN 102 is associated with the HA 106 and the CN 104is associated with a D-HA 108, and wherein the MN 102 is able to movearound and attach to anyone of a plurality of ARs 110, 112, and 114, TheHA 106 includes: (a) a processor 138; and (b) a memory 140 that storesprocessor-executable instructions wherein the processor 138 interfaceswith the memory 140 and executes the processor-executable instructionsto: (i) receive a first message from the MN 102, wherein the firstmessage includes an Internet Protocol address of the CN 104; (ii) usethe Internet Protocol address to identify the D-HA 108; (iii) send asecond message to the D-HA 108, wherein the second message subscribesthe HA 106 at the D-HA 108 for a presence notification service in whichthe D-HA 108 is to update the HA 106 about a care-of address of the CN104 whenever the CN 104 sends the care-of address to the D-HA 108; (iv)receive a third message from the D-HA 108, wherein the third messageidentifies the care-of address of the CN 104; and (v) send a fourthmessage to the MN 102, wherein the fourth message includes the care-ofaddress of the CN 104 which enables a re-direction of data trafficbetween the MN 102 and the CN 104. The HA 106 can also implement amethod which includes the five aforementioned steps (i), (ii), (iii),(iv) and (v).

Those skilled in the art will appreciate that the proposed method 200not only significantly enhances the IP mobility handoff but can befurther optimized when applied in a “pre-defined” mobility context. Infact, the proposed method 200 has multiple advantages including (forexample): (1) no mobility signaling; between two or more mobile nodesexchanging data there between; (2) very low IP handoff latency (i.e.,fast handoff); (3) highly secure; and (4) enable route optimization(RO), i.e., exchange data packets on the direct path.

Although one embodiment of the present invention has been illustrated inthe accompanying Drawings and described in the foregoing DetailedDescription, it should be understood that the invention is not limitedto the disclosed embodiment, but instead is also capable of numerousrearrangements, modifications and substitutions without departing fromthe present invention that as has been set forth and defined within thefollowing claims.

The invention claimed is:
 1. A network for enabling a hybrid routeoptimization between two mobile endpoints including a mobile node and acorrespondent node, the network comprises: a home agent with which themobile node is associated; a destination home agent with which thecorrespondent node is associated; a plurality of access routers anyoneof which the mobile node is attached thereto; the home agent isconfigured to receive a first message sent by the mobile node, whereinthe first message includes an Internet Protocol address of thecorrespondent node; the home agent is configured to use the InternetProtocol address to identify the destination home agent; the home agentis configured to send a second message to at least one of the accessrouters, wherein the second message includes information about themobile node, the correspondent node, and the destination home agent; theat least one of the access routers is configured to send a third messageto the destination home agent, wherein the third message subscribes theat least one of the access routers at the destination home agent for apresence notification service in which the destination home agent is toupdate the at least one of the access routers about a care-of address ofthe correspondent node whenever the correspondent node sends the care-ofaddress to the destination home agent; the destination home agent isconfigured to send a fourth message to the at least one of the accessrouters, wherein the fourth message identifies the care-of address ofthe correspondent node; and one of the at least one of the accessrouters which is configured to receive the fourth message and isattached to the mobile node is further configured to send a fifthmessage to the mobile node, wherein the fifth message includes thecare-of address of the correspondent node which enables a re-directionof data traffic between the mobile node and the correspondent node. 2.The network of claim 1, wherein the first message is a binding updatemessage.
 3. The network of claim 1, wherein the second message is anotification update message that includes: a home address of the mobilenode; a care-of address of the mobile node; the Internet Protocoladdress of the correspondent node; an Internet Protocol address of theD-HA; a lifetime parameter; and a sequence number.
 4. The network ofclaim 1, wherein the third message is a register notification requestmessage that includes: the Internet Protocol address of thecorrespondent node; a lifetime parameter; and a sequence number.
 5. Thenetwork of claim 1, wherein the fourth message is a presencenotification update message that includes: the care-of address of thecorrespondent node; a lifetime parameter; and a sequence number.
 6. Thenetwork of claim 1, wherein the fifth message is an early updatemessage.
 7. A method implemented by an access router for enabling ahybrid route optimization between two mobile endpoints including amobile node and a correspondent node, wherein the mobile node isattached to the access router and associated with a home agent and thecorrespondent node is associated with a destination home agent, whereinthe mobile node sends a first message to the home agent, wherein thefirst message includes an Internet Protocol address of the correspondentnode, wherein the home agent uses the Internet Protocol address toidentify the destination home agent, the method comprises the steps of:receiving, by the access router, a second message from the home agent,wherein the second message includes information about the mobile node,the correspondent node, and the destination home agent; sending, by theaccess router, a third message to the destination home agent, whereinthe third message subscribes the access router at the destination homeagent for a presence notification service in which the destination homeagent is to update the access router about a care-of address of thecorrespondent node whenever the correspondent node sends the care-ofaddress to the destination home agent with the care-of address;receiving, by the access router, a fourth message from the destinationhome agent, wherein the fourth message identifies the care-of address ofthe correspondent node; and sending, by the access router, a fifthmessage to the mobile node, wherein the fifth message includes thecare-of address of the correspondent node which enables a re-directionof data traffic between the mobile node and the correspondent node. 8.The method of claim 7, wherein the second message is a notificationupdate message that includes: a home address of the mobile node; acare-of address of the mobile node; the Internet Protocol address of thecorrespondent node; an Internet Protocol address of the D-HA; a lifetimeparameter; and a sequence number.
 9. The method of claim 7, wherein thethird message is a register notification request message that includes:the Internet Protocol address of the correspondent node; a lifetimeparameter; and a sequence number.
 10. The method of claim 7, wherein thefourth message is a presence notification update message that includes:the care-of address of the correspondent node; a lifetime parameter; anda sequence number.
 11. The method of claim 7, wherein the fifth messageis an early update message.
 12. A destination home agent for enabling ahybrid route optimization between two mobile endpoints including amobile node and a correspondent node, wherein the mobile node isassociated with a home agent and the correspondent node is associatedwith the destination home agent, wherein the mobile node is able to movearound and attach to anyone of a plurality of access routers, whereinthe mobile node sends a first message to the home agent, wherein thefirst message includes an Internet Protocol address of the correspondentnode, wherein the home agent uses the Internet Protocol address toidentify the destination home agent, wherein the home agent sends asecond message to at least one of the access routers, wherein the secondmessage includes information about the mobile node, the correspondentnode, and the destination home agent, the destination home agentcomprises: a processor; and a memory that stores processor-executableinstructions wherein the processor interfaces with the memory andexecutes the processor-executable instructions to: receive a thirdmessage from the at least one of the access routers, wherein the thirdmessage subscribes the at least one of the access routers at thedestination home agent for a presence notification service in which thedestination home agent is to update the at least one of the accessrouters about a care-of address of the correspondent node whenever thecorrespondent node sends the care-of address to the destination homeagent; and send a fourth message to the at least one of the accessrouters, wherein the fourth message identifies the care-of address ofthe correspondent node.
 13. The destination home agent of claim 12,wherein the third message is a register notification request messagethat includes: the Internet Protocol address of the correspondent node;a lifetime parameter; and a sequence number.
 14. The destination homeagent of claim 12, wherein the fourth message is a presence notificationupdate message that includes: the care-of address of the correspondentnode; a lifetime parameter; and a sequence number.
 15. A methodimplemented by a destination home agent for enabling a hybrid routeoptimization between two mobile endpoints including a mobile node and acorrespondent node, wherein the mobile node is associated with a homeagent and the correspondent node is associated with the destination homeagent, wherein the mobile node is able to move around and attach toanyone of a plurality of access routers, wherein the mobile node sends afirst message to the home agent, wherein the first message includes anInternet Protocol address of the correspondent node, wherein the homeagent uses the Internet Protocol address to identify the destinationhome agent, wherein the home agent sends a second message to at leastone of the access routers, wherein the second message includesinformation about the mobile node, the correspondent node, and thedestination home agent, the method comprises the steps of: receiving, bythe destination home agent, a third message from the at least one of theaccess routers, wherein the third message subscribes the at least one ofthe access routers at the destination home agent for a presencenotification service in which the destination home agent is to updatethe at least one of the access routers about a care-of address of thecorrespondent node whenever the correspondent node sends the care-ofaddress to the destination home agent; and sending, by the destinationhome agent, a fourth message to the at least one of the access routers,wherein the fourth message identifies the care-of address of thecorrespondent node.
 16. The method of claim 15, wherein the thirdmessage is a register notification request message that includes: theInternet Protocol address of the correspondent node; a lifetimeparameter; and a sequence number.
 17. The method of claim 15, whereinthe fourth message is a presence notification update message thatincludes: the care-of address of the correspondent node; a lifetimeparameter; and a sequence number.
 18. A method implemented by a homeagent for enabling a hybrid route optimization between two mobileendpoints including a mobile node and a correspondent node, wherein themobile node is associated with the home agent and the correspondent nodeis associated with a destination home agent, wherein the mobile node isable to move around and attach to anyone of a plurality of accessrouters, the method comprises the steps of: receiving, by the homeagent, a first message from the mobile node, wherein the first messageincludes an Internet Protocol address of the correspondent node; using,by the home agent, the Internet Protocol address to identify thedestination home agent; sending, by the home agent, a second message tothe destination home agent, wherein the second message subscribes thehome agent at the destination home agent for a presence notificationservice in which the destination home agent is to update the home agentabout a care-of address of the correspondent node whenever thecorrespondent node sends the care-of address to the destination homeagent; receiving, by the home agent, a third message from thedestination home agent, wherein the third message identifies the care-ofaddress of the correspondent node; and sending, by the home agent, afourth message to the mobile node, wherein the fourth message includesthe care-of address of the correspondent node which enables are-direction of data traffic between the mobile node and thecorrespondent node.